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  • Question 1 - Stroke volume in a average sized man lying in supine position is about?...

    Correct

    • Stroke volume in a average sized man lying in supine position is about?

      Your Answer: 70 ml

      Explanation:

      The stroke volume of an average sized man who is lying is the supine position is about 70 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      23.4
      Seconds
  • Question 2 - Which of the following does not lower ventricular rate in atrial fibrillation? ...

    Correct

    • Which of the following does not lower ventricular rate in atrial fibrillation?

      Your Answer: Adrenaline

      Explanation:

      Adrenaline is a sympathetic neurotransmitter which increases the heart rate. During atrial fibrillation the atria is contracting at more than 200 beats/min. Acetylcholine is a parasympathetic neurotransmitter decreasing the heart rate. Digital also depresses the conduction at the AV conduction. Vagal discharge and occulocardiac reflux decrease the heart rate and convert the tachycardia into normal sinus rhythm.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      61.4
      Seconds
  • Question 3 - The approximate incidence of deep venous thrombosis (DVT) in the general population each...

    Incorrect

    • The approximate incidence of deep venous thrombosis (DVT) in the general population each year is:

      Your Answer: 50 per 1000

      Correct Answer: 1 per 1000

      Explanation:

      About 1 in 1000 adults per year has DVT, but as of 2011, available data is dominated by North American and European populations. DVT is rare in children, with an incidence of about 1 in 100,000 a year. From childhood to old age, incidence increases by a factor of about 1000, with almost 1% of the elderly experiencing DVTs yearly.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      16.1
      Seconds
  • Question 4 - Vasodilatation of coronary arteries is caused by: ...

    Correct

    • Vasodilatation of coronary arteries is caused by:

      Your Answer: Hypoxia

      Explanation:

      The heart is highly metabolically active and boasts the highest oxygen consumption by mass of any organ. This demand for oxygen is met by the coronary circulation, which is responsible for delivering blood to the myocardium and represents approximately 5% of cardiac output. Vasodilation may be due to the local effect of hypoxia on coronary vessels, or local metabolic vasodilation, or the activation of β-adrenoceptors or some combination of these mechanisms.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      15.4
      Seconds
  • Question 5 - Which of the following would be a contraindication to thrombolysis? ...

    Correct

    • Which of the following would be a contraindication to thrombolysis?

      Your Answer: Intracranial neoplasm

      Explanation:

      Absolute contraindications to thrombolysis include:

      • Previous intracranial bleeding at any time
      • Stroke in less than 6 months
      • Closed head or facial trauma within 3 months
      • Suspected aortic dissection
      • Ischemic stroke within 3 months (except in ischemic stroke within 3 hours time)
      • Active bleeding diathesis
      • Uncontrolled high blood pressure (>180 systolic or >100 diastolic)
      • Known structural cerebral vascular lesion
      • Arterio-venous malformations
      • Thrombocytopenia
      • Known coagulation disorders
      • Aneurysm
      • Brain tumours
      • Pericardial effusion
      • Septic embolus

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      34.9
      Seconds
  • Question 6 - Describe the location of the SA node: ...

    Incorrect

    • Describe the location of the SA node:

      Your Answer: Just above the tricuspid valve

      Correct Answer: Junction of the SVC and right atrium

      Explanation:

      Anatomically the SA node is located at the junction of the superior vena cava and the right atrium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      33.5
      Seconds
  • Question 7 - Concerning surface anatomy, where is the aortic valve found? ...

    Incorrect

    • Concerning surface anatomy, where is the aortic valve found?

      Your Answer: Situated in the right second intercostal space underneath the sternum

      Correct Answer: Situated in the left third intercostal space underneath the sternum

      Explanation:

      The aortic valve is situated in the left 3rd intercostal space just beneath the sternum.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      36.7
      Seconds
  • Question 8 - The effects of β1 stimulation include the following ...

    Correct

    • The effects of β1 stimulation include the following

      Your Answer: Increased strength of contraction

      Explanation:

      β1 stimulation include the phosphorylation of L type Ca++ channels and phospholamban and increased Ca++ influx from myocytes.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      45.8
      Seconds
  • Question 9 - Myocardial oxygen consumption is increased by: ...

    Correct

    • Myocardial oxygen consumption is increased by:

      Your Answer: An increase in after load

      Explanation:

      Cardiac oxygen consumption is directly related to the amount of tension that develops in the ventricles. It is increased by an increased size of heart, increased afterload, increased contractility and increased heart rate.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      39.6
      Seconds
  • Question 10 - How many molecules of myosin attach to actin at any given time? ...

    Incorrect

    • How many molecules of myosin attach to actin at any given time?

      Your Answer: 2

      Correct Answer: 1

      Explanation:

      1 molecule of myosin binds to actin at any give time.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.7
      Seconds
  • Question 11 - Tunica intima is made up of? ...

    Correct

    • Tunica intima is made up of?

      Your Answer: Endothelial cells

      Explanation:

      Tunica intima is a single cell thick lining of endothelial cells that lines the inside of the blood vessels. It is the inner most layer of the blood vessel.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.7
      Seconds
  • Question 12 - Which vagus nerve mainly supplies the AV node? ...

    Correct

    • Which vagus nerve mainly supplies the AV node?

      Your Answer: Left vagus

      Explanation:

      As the AV node develops from the left side of the embryo It is supplied by the left vagus nerve.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.1
      Seconds
  • Question 13 - Regarding the cardiac muscle striations as viewed under the microscope, which areas are...

    Correct

    • Regarding the cardiac muscle striations as viewed under the microscope, which areas are dark?

      Your Answer: A band and z line

      Explanation:

      Dark bands: a, h. Dark line: z. Clear band: i, m

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      45.9
      Seconds
  • Question 14 - Digoxin causes: ...

    Incorrect

    • Digoxin causes:

      Your Answer: Na/k ATPase stimulation

      Correct Answer: Increase in cytosolic calcium concentration

      Explanation:

      Digoxin is a positive inotrope which inhibits NA/K ATPase, increases cardiac contractility and can cause hypokalaemia.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      41.1
      Seconds
  • Question 15 - Which of the following components regulate cardiac output? ...

    Correct

    • Which of the following components regulate cardiac output?

      Your Answer: All of the above

      Explanation:

      Cardiac output is regulated by the autonomic nervous system with sympathetic nerves having a positive chronotropic and inotropic effect and parasympathetic nerves having the opposite effect. An increase in preload will increase cardiac output likewise an afterload increase will also increase cardiac output.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      21.1
      Seconds
  • Question 16 - Which of the following affects the magnitude of the action potential? ...

    Incorrect

    • Which of the following affects the magnitude of the action potential?

      Your Answer: Changes in the intracellular K+ concentration

      Correct Answer: Changes in the external Na+ concentration

      Explanation:

      The magnitude of the action potential is determined by the sodium current. Increase in external sodium will result in increased influx of sodium and hence generation of a stronger action potential.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      22.9
      Seconds
  • Question 17 - The coronary sinus, which empties into the right atrium, serves to? ...

    Correct

    • The coronary sinus, which empties into the right atrium, serves to?

      Your Answer: Drain the venous supply of the myocardium

      Explanation:

      The coronary sinus is a collection of veins joined together to form a large vessel that collects blood from the heart muscle (myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior vena cava.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      16.2
      Seconds
  • Question 18 - According to Starling's law of the heart: ...

    Incorrect

    • According to Starling's law of the heart:

      Your Answer: Energy of contraction is proportional to the pressure in the left ventricle

      Correct Answer: The extent of the preload is proportional to the end-diastolic volume

      Explanation:

      Frank starlings law describes that an increase in the venous return or the end diastolic volume will cause an increase in the stroke volume/ preload and also cardiac output. It stems from the fact that increased venous return will increase the stretch on the ventricular muscle fibers. The sarcomere will stretch a considerable length that is needed for maximum contraction and the development of tension in the muscle fiber. The greater the venous return the greater the cardiac output. This relationship is directly proportional.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      27.8
      Seconds
  • Question 19 - What is the main reason for checking the urea and electrolytes prior to...

    Incorrect

    • What is the main reason for checking the urea and electrolytes prior to commencing a patient on amiodarone?

      Your Answer: To detect impaired renal function

      Correct Answer: To detect hypokalaemia

      Explanation:

      All antiarrhythmic drugs have the potential to cause arrhythmias. Coexistent hypokalaemia significantly increases this risk.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      32.8
      Seconds
  • Question 20 - Coronary flow is reduced during ...

    Incorrect

    • Coronary flow is reduced during

      Your Answer: Ventricular filling

      Correct Answer: Tachycardia

      Explanation:

      Maximum amount of blood flow in the coronary arteries occur during diastole. When the heart rate increases which is also called tachycardia the duration of diastole decreases. Hence the amount of blood flow to the cardiac muscle also decreases.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      30.1
      Seconds
  • Question 21 - Myocardium requires more oxygen to expel blood in: ...

    Correct

    • Myocardium requires more oxygen to expel blood in:

      Your Answer: A stenotic aortic valve

      Explanation:

      In aortic valve stenosis, increased ventricular pressure Is needed to expel the blood into the aorta. Increased pressure means increased contractility hence increase O2 consumption by the heart muscles.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      21.5
      Seconds
  • Question 22 - If both the noradrenergic and the cholinergic systems are blocked in the heart,...

    Incorrect

    • If both the noradrenergic and the cholinergic systems are blocked in the heart, the rate will be approximately:

      Your Answer: 70/min

      Correct Answer: 100/min

      Explanation:

      The normal heart beat is about 70/min. This is due to a predominant parasympathetic activity. If sympathetic activity was unopposed the heart rate would have been 150/min. When both the noradrenergic and cholinergic systems are blocked the heart rate is 100/min. This is the normal firing rate of the SA node.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      21.6
      Seconds
  • Question 23 - In the blood supply of the heart, ‘dominance’ refers to the coronary artery...

    Correct

    • In the blood supply of the heart, ‘dominance’ refers to the coronary artery which supplies the?

      Your Answer: Posterior interventricular artery

      Explanation:

      Dominance of the coronary artery system is defined by the artery that gives rise to the posterior interventricular artery. Dominance of the right coronary artery is more common (68%). It gives rise to the large posterior interventricular branch which goes down to the apex of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      41.7
      Seconds
  • Question 24 - Concerning surface anatomy, where is the base of the heart ...

    Incorrect

    • Concerning surface anatomy, where is the base of the heart

      Your Answer: 5th intercostal space mid clavicular line

      Correct Answer: 2nd left costal to 3rd right costal cartilage

      Explanation:

      The base of the heart, also known as the superior border of the heart corresponds to a line connecting the inferior border of the 2nd left costal cartilage to the superior border of the 3rd right costal cartilage.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.7
      Seconds
  • Question 25 - Normal stroke volume is about: ...

    Correct

    • Normal stroke volume is about:

      Your Answer: 70 ml

      Explanation:

      Stroke volume is the amount of blood that is pumped from the heart into the aorta. It is typically 70 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.5
      Seconds
  • Question 26 - A 27-year-old man presents with a regular tachycardia of 190 bpm. He is...

    Correct

    • A 27-year-old man presents with a regular tachycardia of 190 bpm. He is healthy and has no past medical history. Blood pressure and blood tests are all within normal parameters however the ECG confirms a narrow complex tachycardia. The tachycardia persists after giving IV adenosine 6mg. What should be the next step in management of this patient?

      Your Answer: IV 12mg adenosine

      Explanation:

      For narrow complex tachycardias with no compromise then vagal manoeuvres should be trialled first. The Valsalva manoeuvre should be the first vagal manoeuvre tried and works by increasing intra-thoracic pressure and affecting baroreceptors (pressure sensors) within the arch of the aorta. It is carried out by asking the patient to hold his/her breath while trying to exhale forcibly as if straining during a bowel movement. Adenosine, an ultra-short-acting AV nodal blocking agent, is indicated if vagal manoeuvres are not effective. Adenosine may be safely used during pregnancy. In adults the recommended first dose of intravenous adenosine is 6 mg. The dose is administered rapidly and then followed by a saline flush. Adenosine is only present in the circulation for about 5 seconds, so it is an excellent drug for diagnosis and treatment. If there was a response to adenosine but it was not long lasting, an additional dose of 12 mg of adenosine intravenously can be attempted. Doses greater than 12 mg are not recommended. If adenosine fails then Verapamil or a beta blocker can be used as alternatives. If the patient is hemodynamically unstable or other treatments have not been effective, synchronized electrical cardioversion may be used.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      35.1
      Seconds
  • Question 27 - Impulse conduction through the AV node is slow and depends on the action...

    Correct

    • Impulse conduction through the AV node is slow and depends on the action potential produced by which of the following.

      Your Answer: Calcium flux

      Explanation:

      The action potentials in the SA and AV nodes are largely due to Ca2+, with no contribution by Na+ influx.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      40.4
      Seconds
  • Question 28 - Which of the following structures of the cardiac conduction system is located in...

    Incorrect

    • Which of the following structures of the cardiac conduction system is located in the right posterior portion of the interatrial septum?

      Your Answer: SA node

      Correct Answer: AV node

      Explanation:

      AV node is located at the right posterior portion of the interatrial septum.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      21.6
      Seconds
  • Question 29 - Initial depolarization of cardiac muscle is due to influx of: ...

    Correct

    • Initial depolarization of cardiac muscle is due to influx of:

      Your Answer: Na+

      Explanation:

      Initial depolarization of the cardiac muscle results from opening of the sodium voltage gated channels. This results in the influx of sodium and an increase in the membrane potential towards threshold. Potassium efflux results in repolarization.

      The cardiac action potential has 5 phases:

      • Phase 0—depolarization because of the opening of fast sodium channels. Potassium flux also decreases.
      • Phase 1—partial repolarization because of a rapid decrease in sodium ion passage as fast sodium channels close.
      • Phase 2—plateau phase in which the movement of calcium ions out of the cell, maintains depolarization.
      • Phase 3—repolarization, sodium, and calcium channels all close and membrane potential returns to baseline.
      • Phase 4—resting membrane potential (−90 mV), resulting from the activity of the Na+/K+ ATPase pump which creates a negative intracellular potential because of the exchange of three sodium ions for only two potassium ions.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      38.6
      Seconds
  • Question 30 - Why is the sub-endocardial portion of the left ventricle the most common site...

    Correct

    • Why is the sub-endocardial portion of the left ventricle the most common site for ischaemic damage and myocardial infarction?

      Your Answer: No blood flow occurs during systole

      Explanation:

      The subendocardium receives the least amount of blood from the coronary arteries. During systole the coronary arteries collapse as a result of the pressure due to contraction that is exerted on them. During diastole the heart muscle relaxes and the pressure on the coronary vessels is relieved allowing blood to flow through them to the subendocardium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      35
      Seconds
  • Question 31 - What is the isolated effect of B2 stimulation on the coronaries? ...

    Correct

    • What is the isolated effect of B2 stimulation on the coronaries?

      Your Answer: Vasodilatation

      Explanation:

      Norepinephrine and epinephrine are agonists for all adrenergic receptor subtypes, although with varying affinities. Based on their physiology and pharmacology, adrenergic receptors have been divided into two principal types: alpha and beta. These types have been further differentiated into alpha-1, alpha-2, b1, and b2 receptors.

      Alpha-1 Receptors are located on postsynaptic cells in smooth muscle and elicit vasoconstriction.

      Alpha-2 receptors are localized on presynaptic membranes of postganglionic nerve terminals that synthesize norepinephrine. When activated by catecholamines, alpha-2 receptors act as negative feedback controllers, inhibiting further norepinephrine release.

      Activation of myocardial b1 receptors stimulates the rate and strength of cardiac contraction, and consequently increases cardiac output. b1 Receptor activation also stimulates renin release from the kidney. Another class of antihypertensive agents acts by inhibiting b1 receptors.

      Activation of b2 receptors by epinephrine relaxes vascular smooth muscle and results in vasodilation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.9
      Seconds
  • Question 32 - The a-wave is created by: ...

    Correct

    • The a-wave is created by:

      Your Answer: Regurgitation of some blood to the great veins when the atria contracts in atrial systole

      Explanation:

      The a-wave created on the venous pulse curve occurs as a result of atrial systole. Due to the pressure build-up in the atria, it causes a back pressure in the vena cava. This pressure is exerted on the valve and this back pressure is what causes a slight increase in the venous pressure.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      24.7
      Seconds
  • Question 33 - Heart rate can be slowed by: ...

    Incorrect

    • Heart rate can be slowed by:

      Your Answer: Hypoxia

      Correct Answer: Grief

      Explanation:

      Grief stimulates the parasympathetic nervous system, resulting in a decrease in the heart rate.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      11.6
      Seconds
  • Question 34 - What is the function of the BK channel on the vascular smooth muscle...

    Correct

    • What is the function of the BK channel on the vascular smooth muscle membrane?

      Your Answer: Massive K+ efflux, increasing membrane potential, and shutting off the voltage gated Ca2+ channel

      Explanation:

      BK channels, also known as large-conductance calcium-activated potassium channels, play a critical role in regulating vascular smooth muscle tone. When BK channels open, they allow a large efflux of potassium ions (K+) out of the cell. This efflux of K+ causes the membrane potential to become more negative (hyperpolarization), which in turn leads to the closure of voltage-gated calcium channels. The closure of these calcium channels reduces the influx of calcium ions (Ca2+) into the smooth muscle cells, resulting in decreased intracellular calcium levels and subsequent relaxation of the smooth muscle.

      Thus, BK channels promote smooth muscle relaxation by hyperpolarizing the membrane and reducing the activity of voltage-gated Ca2+ channels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      49.9
      Seconds
  • Question 35 - The major factor in controlling coronary artery blood flow is considered to be?...

    Correct

    • The major factor in controlling coronary artery blood flow is considered to be?

      Your Answer: Metabolites of oxygen consumption

      Explanation:

      There is a strong relationship between myocardial blood flow and oxygen consumption. This indicates that products of metabolism may cause vasodilation of the coronary artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      21.7
      Seconds
  • Question 36 - The Sinoatrial node in the majority of people is supplied by the? ...

    Correct

    • The Sinoatrial node in the majority of people is supplied by the?

      Your Answer: Right coronary artery

      Explanation:

      In 60% of people, the SA node is supplied by the right coronary artery branch and in 40% of the people by the left coronary artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      12.3
      Seconds
  • Question 37 - Troponin I is inhibited by calcium binding to: ...

    Incorrect

    • Troponin I is inhibited by calcium binding to:

      Your Answer: Tropomyosin

      Correct Answer: Troponin c

      Explanation:

      At rest troponin I is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin I which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      17.9
      Seconds
  • Question 38 - Which of the following is NOT true of the parasympathetic control of the...

    Correct

    • Which of the following is NOT true of the parasympathetic control of the heart?

      Your Answer: It can be blocked by beta blockers

      Explanation:

      Parasympathetic fibers do not innervate the Beta receptors on the heart. They are innervated by the sympathetic nerve fibers. Then a beta blocker such as propranolol will block the sympathetic outflow and increase the parasympathetic tone of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      20
      Seconds
  • Question 39 - Which of the following makes up the thick filaments in muscle fibers? ...

    Correct

    • Which of the following makes up the thick filaments in muscle fibers?

      Your Answer: Myosin

      Explanation:

      The thick filaments are made up of myosin and the thin filaments are made up of actin. The thick filaments are twice the size of the thin filaments and are aligned to form the A band. The thin filaments extending out from the A band form the less dense I bands.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7.6
      Seconds
  • Question 40 - Which coronary artery supplies the right atria? ...

    Correct

    • Which coronary artery supplies the right atria?

      Your Answer: Right coronary

      Explanation:

      The left coronary artery distributes blood to the left side of the heart, the left atrium and ventricle, and the interventricular septum. The circumflex artery arises from the left coronary artery and follows the coronary sulcus to the left. Eventually, it will fuse with the small branches of the right coronary artery. The right coronary artery proceeds along the coronary sulcus and distributes blood to the right atrium, portions of both ventricles, and the heart conduction system.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      8.2
      Seconds
  • Question 41 - The isoforms of nitric oxide synthase which are found in the nervous system...

    Incorrect

    • The isoforms of nitric oxide synthase which are found in the nervous system (NOS1) and endothelial cells (NOS3) are activated by agents that increase which of the following intracellular electrolytes?

      Your Answer: K

      Correct Answer: Ca

      Explanation:

      Synthesis of nitric oxide is stimulated by activation of the NMDA receptors by certain agents. This leads to opening of the Calcium channels and an influx of calcium into the cell. This will activate the nitric oxide synthase. Nitric oxide is produced on demand.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      25
      Seconds
  • Question 42 - Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?...

    Correct

    • Depolarization of the T tubule membrane activates the sarcoplasmic reticulum via which receptors?

      Your Answer: Dihydropyridine receptors

      Explanation:

      Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ form the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors.

      Dihydropyridine receptors (DHPRs), are voltage-gated Ca2+ channels, and ryanodine receptors (RyRs), which are intracellular Ca2+ release channels, are expressed in diverse cell types, including skeletal and cardiac muscle.

      Ryanodine receptors (RyRs) are located in the sarcoplasmic/endoplasmic reticulum membrane and are responsible for the release of Ca2+ from intracellular stores during excitation-contraction coupling in both cardiac and skeletal muscle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      16.7
      Seconds
  • Question 43 - The branche(s) of the left coronary artery include: ...

    Correct

    • The branche(s) of the left coronary artery include:

      Your Answer: Left circumflex artery & anterior interventricular artery

      Explanation:

      The left main coronary divides into branches:

      1. The left anterior descending artery branches off the left coronary artery and supplies blood to the front of the left side of the heart.

      2. The circumflex artery branches off the left coronary artery and encircles the heart muscle.

      The anterior interventricular artery is otherwise known as the anterior descending branch. The posterior descending artery comes from Right coronary artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.5
      Seconds
  • Question 44 - Direct conduction from the atrium to the ventricles is prevented by: ...

    Correct

    • Direct conduction from the atrium to the ventricles is prevented by:

      Your Answer: Annulus fibrosus

      Explanation:

      The annulus fibrosus disconnects the syncytium complex. The atria are rapidly activated however the activation peters out when the insulating layer-the annulus fibrosus-is reached.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.9
      Seconds
  • Question 45 - The rate of depolarisation of the sinus node membrane potential is modulated by...

    Correct

    • The rate of depolarisation of the sinus node membrane potential is modulated by all the following except:

      Your Answer: Cardiac output

      Explanation:

      Cardiac output has no effect on the depolarization of the pacemaker potential of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      19.6
      Seconds
  • Question 46 - Endothelial cells are attached to adjacent cells by adherent junctions via: ...

    Incorrect

    • Endothelial cells are attached to adjacent cells by adherent junctions via:

      Your Answer: Integrins

      Correct Answer: Cadherins

      Explanation:

      Cadherins are calcium dependant molecules that mediate cell to cell adhesions in epithelial and endothelial cells among others.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      15.9
      Seconds
  • Question 47 - Which structure forms the major part of the sternocostal surface of the heart?...

    Incorrect

    • Which structure forms the major part of the sternocostal surface of the heart?

      Your Answer: Left atrium

      Correct Answer: Right ventricle

      Explanation:

      The anterior (sternocostal) surface is formed mainly by the right ventricle.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.5
      Seconds
  • Question 48 - Regarding the length of systole and diastole which of the following is true?...

    Incorrect

    • Regarding the length of systole and diastole which of the following is true?

      Your Answer: At very rapid heart rates diastole is adequate

      Correct Answer: The duration of systole is more fixed than diastole

      Explanation:

      The duration of systole is more fixed than the duration of diastole. When the heart rate increases the timing of systole remains more or less the same however, diastole decreases.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      69.6
      Seconds
  • Question 49 - Vasodilatation in skeletal muscle can be caused by: ...

    Correct

    • Vasodilatation in skeletal muscle can be caused by:

      Your Answer: Sympathetic cholinergic nerves

      Explanation:

      In skeletal muscles some fibers that cause vasodilation run with the nerves of the sympathetic system but are cholinergic in nature. These nerves are not active during rest but become active during exercise and stress.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      70.2
      Seconds
  • Question 50 - AV valves open during? ...

    Incorrect

    • AV valves open during?

      Your Answer: None of the above

      Correct Answer: Early diastole

      Explanation:

      The cardiac cycle refers to a complete heartbeat from its generation to the beginning of the next beat, and so includes the diastole, the systole, and the intervening pause.The first stage, diastole, is when the semilunar valves (the pulmonary valve and the aortic valve) close, the atrioventricular (AV) valves (the mitral valve and the tricuspid valve) open, and the whole heart is relaxed. The second stage, atrial systole, is when the atrium contracts, and blood flows from atrium to the ventricle.The third stage, isovolumic contraction is when the ventricles begin to contract, the AV and semilunar valves close, and there is no change in volume. The fourth stage, ventricular ejection, is when the ventricles are contracting and emptying, and the semilunar valves are open. During the fifth stage, isovolumic relaxation time, pressure decreases, no blood enters the ventricles, the ventricles stop contracting and begin to relax, and the semilunar valves close due to the pressure of blood in the aorta.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      25.3
      Seconds
  • Question 51 - Which of the following conditions does not influence the cardiac output? ...

    Correct

    • Which of the following conditions does not influence the cardiac output?

      Your Answer: Sleep

      Explanation:

      Sleep has no effect on the cardiac output.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      21.2
      Seconds
  • Question 52 - In ventricular fibrillation (VF), the first defibrillation attempt (with a biphasic defibrillator) should...

    Correct

    • In ventricular fibrillation (VF), the first defibrillation attempt (with a biphasic defibrillator) should be made at:

      Your Answer: 200 J

      Explanation:

      Defibrillation is a common treatment for life-threatening cardiac dysrhythmias and ventricular fibrillation. If the patient is in Ventricular tachycardia (VT) or ventricular fibrillation (VF) on the monitor, immediately apply the pads and shock the patient with 120-200 Joules on a biphasic defibrillator or 360 Joules on a monophasic defibrillator.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      11.4
      Seconds
  • Question 53 - Closure of the tricuspid valve is marked by which of the following features...

    Incorrect

    • Closure of the tricuspid valve is marked by which of the following features of the jugular venous waveform?

      Your Answer: a wave

      Correct Answer: c wave

      Explanation:

      The jugular venous pressure (JVP) classically has three upward deflections and two downward deflections. The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling. The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      18.9
      Seconds
  • Question 54 - Calcium needed for cardiac muscle contraction is made available during which phase of...

    Incorrect

    • Calcium needed for cardiac muscle contraction is made available during which phase of the action potential?

      Your Answer: 1

      Correct Answer: 2

      Explanation:

      It is made available during the plateau phase of the action potential i.e. phase 2. During the plateau phase of the action potential, Calcium from the extracellular fluid enters through the L type of calcium channels. This entry triggers the release of more calcium from the sarcoplasmic reticulum via the ryanodine receptors.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      46.8
      Seconds
  • Question 55 - Regarding the surface anatomy of the orifices of the heart, where is the...

    Incorrect

    • Regarding the surface anatomy of the orifices of the heart, where is the aortic valve located?

      Your Answer: Opposite the left upper sternal border in the 2nd intercostal space

      Correct Answer: Opposite the left 3rd intercostal space to the left of the sternum

      Explanation:

      The aortic valve is situated in the left 3rd intercostal space just beneath the sternum.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      43.5
      Seconds
  • Question 56 - Adrenergic stimulation will lead to myocyte relaxation via the following mechanisms ...

    Correct

    • Adrenergic stimulation will lead to myocyte relaxation via the following mechanisms

      Your Answer: Increased phosphorylation of phosholamban

      Explanation:

      Phosphorylation of phospholamban, which increases calcium ATPase activity and sequestration of calcium in the sarcoplasmic reticulum. An increased rate of relaxation is explained because cAMP also activates the protein phospholamban, situated on the membrane of the SR, that controls the rate of uptake of calcium into the SR. The latter effect explains enhanced relaxation (lusitropic effect).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      32.7
      Seconds
  • Question 57 - Which of the following concerning PR interval is INCORRECT? ...

    Incorrect

    • Which of the following concerning PR interval is INCORRECT?

      Your Answer: Shorter in children than in adults

      Correct Answer: Always measured from the beginning of p wave to the beginning of r wave

      Explanation:

      The PR interval measures the time from the start of atrial depolarization to the start of ventricular depolarization. The PR interval is only measured from the beginning of P wave to beginning of R wave if the Q wave is absent.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      32.4
      Seconds
  • Question 58 - Which of the following results in the resting membrane potential of a myocyte?...

    Incorrect

    • Which of the following results in the resting membrane potential of a myocyte?

      Your Answer: Activation of gated Na channels

      Correct Answer: Activation of outward K+ channels

      Explanation:

      Phase 0 is caused by the sodium current. Voltage gated sodium channels open leading to the influx of sodium into the cardiac muscle cell. Phase 1 is the rapid transient repolarization phase which is caused by the inactivation of the voltage gated sodium channels and opening of the voltage gated potassium channels along with opening of the slow calcium channels. Phase 2 which is the plateau is caused by opening of the slow calcium channels. Phase 4 is caused by closing of the slow calcium channels and opening of the potassium channels leading to efflux of potassium leading to the establishment of the resting membrane potential.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      41.1
      Seconds
  • Question 59 - Which of the following does not contribute to increased stroke volume during exercise?...

    Incorrect

    • Which of the following does not contribute to increased stroke volume during exercise?

      Your Answer: Increased sympathetic stimulation of ventricular muscle

      Correct Answer: Increased length of filling time during diastole

      Explanation:

      Prolonged aerobic exercise training may also increase stroke volume, which frequently results in a lower (resting) heart rate. Reduced heart rate prolongs ventricular diastole (filling), increasing end-diastolic volume, and ultimately allowing more blood to be ejected.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      31.4
      Seconds
  • Question 60 - The triangle with the heart at its centre, using limb leads is called:...

    Correct

    • The triangle with the heart at its centre, using limb leads is called:

      Your Answer: Einthoven

      Explanation:

      The Einthoven triangle is formed by placing the limb leads on both the arms and on the left leg with the heart in the centre.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      5.3
      Seconds
  • Question 61 - When the heart rate is increased (to pathological levels) which of the following...

    Incorrect

    • When the heart rate is increased (to pathological levels) which of the following is correct when comparing the duration of diastole to systole?

      Your Answer: It is lengthened to a greater degree

      Correct Answer: It is shortened to a greater degree

      Explanation:

      The duration of systole is more fixed than the duration of diastole. When the heart rate increases the timing of the systole remains more or less the same however diastole decreases.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      35
      Seconds
  • Question 62 - Which of the following supplies the AV node? ...

    Incorrect

    • Which of the following supplies the AV node?

      Your Answer: Left anterior descending

      Correct Answer: Right coronary artery

      Explanation:

      The AV node is supplied by the right coronary artery near the origin of the posterior IV artery.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      19.1
      Seconds
  • Question 63 - Which of the atrial pressure changes represents the a-wave of the JVP ...

    Correct

    • Which of the atrial pressure changes represents the a-wave of the JVP

      Your Answer: Atrial systole

      Explanation:

      The a-wave created on the venous pulse curve occurs as a result of atrial systole. Due to the pressure build-up in the atria, it causes a back pressure in the vena cava. This pressure is exerted on the valve and this back pressure is what causes a slight increase in the venous pressure.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      34.5
      Seconds
  • Question 64 - Which of the following is true with AV nodal delay? ...

    Incorrect

    • Which of the following is true with AV nodal delay?

      Your Answer: The delay is about 0.01s

      Correct Answer: Shortened by sympathetic stimulation

      Explanation:

      AV nodal delay Is about 0.1s before the action potential spreads to the ventricles. It is shortened by stimulation of the sympathetic nervous system and lengthened by stimulation of the parasympathetic system.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.4
      Seconds
  • Question 65 - Which of the following corresponds to an oblique line drawn from the sternal...

    Incorrect

    • Which of the following corresponds to an oblique line drawn from the sternal end of the left 3rd costal cartilage to the sternal end of the right 6th costal cartilage?

      Your Answer: Inter-ventricular septum

      Correct Answer: Atrio-ventricular (coronary) groove

      Explanation:

      The AV groove corresponds to the right border of the heart. The right border corresponds to a line drawn from the 3rd right costal cartilage to the 6th right costal cartilage; this border is slightly convex to the right.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      54.2
      Seconds
  • Question 66 - The SA and AV nodes are usually supplied by which artery? ...

    Correct

    • The SA and AV nodes are usually supplied by which artery?

      Your Answer: Right coronary artery

      Explanation:

      The right coronary artery supplies the right atrium, right ventricle, SA and AV nodes.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.3
      Seconds
  • Question 67 - Isovolumetric ventricular contraction lasts for? ...

    Incorrect

    • Isovolumetric ventricular contraction lasts for?

      Your Answer: 0,01 s

      Correct Answer: 0,05 s

      Explanation:

      Isovolumetric contraction lasts for about 0.05 seconds.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      6.3
      Seconds
  • Question 68 - Regarding cardiac contractility, catecholamines exert their inotropic effect via: ...

    Incorrect

    • Regarding cardiac contractility, catecholamines exert their inotropic effect via:

      Your Answer: Î’2-adrenergic receptors and gs

      Correct Answer: Î’1-adrenergic receptors and gs

      Explanation:

      Catecholamines exert their inotropic effect on the heart via the B1 adrenergic receptors and Gs, stimulating adenyl cyclase and increasing the production of cAMP.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      23.9
      Seconds
  • Question 69 - Relaxation of the cardiac muscle at the actin-myosin cross bridges is initiated by...

    Incorrect

    • Relaxation of the cardiac muscle at the actin-myosin cross bridges is initiated by binding of which molecule to the exposed site on the myosin.

      Your Answer: None of the above

      Correct Answer: ATP

      Explanation:

      A crossbridge is a myosin projection, consisting of two myosin heads, that extends from the thick filaments. Each myosin head has two binding sites: one for ATP and another for actin. The binding of ATP to a myosin head detaches myosin from actin, thereby allowing myosin to bind to another actin molecule. Once attached, the ATP is hydrolysed by myosin, which uses the released energy to move into the cocked position whereby it binds weakly to a part of the actin binding site.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      69.7
      Seconds
  • Question 70 - The end- diastolic ventricular volume is about? ...

    Correct

    • The end- diastolic ventricular volume is about?

      Your Answer: 130 ml

      Explanation:

      The end diastolic volume in a healthy individual is about 130 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      7
      Seconds
  • Question 71 - The T-tubular system in cardiac muscle is: ...

    Correct

    • The T-tubular system in cardiac muscle is:

      Your Answer: Transmits action potential from sarcolemma to the SR to allow for Ca2+ release into the cytoplasm

      Explanation:

      Action potentials are transmitted to the fibrils of a fiber through the T tubule system. It triggers the release of Ca 2+ from the terminal cisterns. Depolarization of the T tubules activates the sarcoplasmic reticulum through the dihydropyridine receptors, which are voltage gated calcium channels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      74.3
      Seconds
  • Question 72 - The Plateau phase in myocyte action potentials does all of the following except:...

    Correct

    • The Plateau phase in myocyte action potentials does all of the following except:

      Your Answer: It allows early reactivation of the myocytes

      Explanation:

      The presence of the plateau in the action potential causes ventricular contraction to last as much as 15 times longer in cardiac muscle as in skeletal muscle. The plateau phase which follows is unique to myocytes and results from a small, but sustained inward calcium current through L-type calcium channels lasting 200-400 ms. This calcium influx is caused by a combined increase in permeability of the cell and especially the sarcolemmal membranes to calcium. This plateau (refractory) phase prevents early reactivation of the myocytes and directly determines the strength of contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      27.6
      Seconds
  • Question 73 - Which of the following causes the closure of the ductus arteriosus during birth?...

    Incorrect

    • Which of the following causes the closure of the ductus arteriosus during birth?

      Your Answer: Reduction of pulmonary vascular resistance

      Correct Answer: Reduced levels of prostaglandins

      Explanation:

      Ductus arteriosus is kept open by the prostaglandin E2 which is a vasodilator. At birth the high levels of cyclooxygenase blocks the production of prostaglandins which results in the closure of the ductus arteriosus.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      23.8
      Seconds
  • Question 74 - Regarding cardiac output, an increased ejection fraction results from increases in which of...

    Correct

    • Regarding cardiac output, an increased ejection fraction results from increases in which of the following?

      Your Answer: Strength of contraction without increase in muscle fiber length

      Explanation:

      When the strength of contraction increases without an increase in fiber length, the EF increases.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      108.8
      Seconds
  • Question 75 - B1 adrenergic stimulation produces: ...

    Correct

    • B1 adrenergic stimulation produces:

      Your Answer: Increase in calcium cytosolic concentration

      Explanation:

      Norepinephrine secreted by the sympathetic endings binds to B1 receptors, and the resulting increase in intracellular cAMP facilitates the opening of L channels, increasing Ica and the rapidity of the depolarization phase of the impulse and activates PKA which leads to phosphorylation of the voltage-gated Ca2+ channels, causing them to spend more time in the open state.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      22.3
      Seconds
  • Question 76 - Which of the following suggests the presence of mitral regurgitation as well as...

    Incorrect

    • Which of the following suggests the presence of mitral regurgitation as well as mitral stenosis?

      Your Answer: Loud P2

      Correct Answer: Displaced apex beat

      Explanation:

      Mitral stenosis on its own does not lead to left ventricular dilatation and hence a displaced apex beat. Thus a displaced apex beat is suggestive of mixed mitral disease. The other options occur in mitral stenosis.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      42.5
      Seconds
  • Question 77 - The celiac trunk consists of which arteries? ...

    Correct

    • The celiac trunk consists of which arteries?

      Your Answer: Left gastric, common hepatic, splenic

      Explanation:

      The celiac trunk is the first major branch of the abdominal aorta. It is 1.25 cm in length. Branching from the aorta at thoracic vertebra 12 (T12). There are three main divisions of the celiac artery:- left gastric artery- common hepatic artery- splenic artery

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13.1
      Seconds
  • Question 78 - The average end diastolic volume in a healthy individual’s ventricle is? ...

    Correct

    • The average end diastolic volume in a healthy individual’s ventricle is?

      Your Answer: 130 ml

      Explanation:

      The end diastolic volume in a healthy individual is about 130 ml.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      9.9
      Seconds
  • Question 79 - Which vaso metabolite decreases coronary blood flow? ...

    Correct

    • Which vaso metabolite decreases coronary blood flow?

      Your Answer: Endothelin

      Explanation:

      Decreased O2, increased CO2, lactate, prostaglandins, adenine nucleotides, adenosine, H+, K+ and cyanide produce vasodilation and thus an increase in coronary blood flow.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      16.7
      Seconds
  • Question 80 - What is troponin? ...

    Incorrect

    • What is troponin?

      Your Answer: A myosin light chain

      Correct Answer: A component of thin filaments

      Explanation:

      Skeletal muscle cytoplasmic proteins include myosin and actin (also known as thick and thin filaments, respectively) which are arranged in a repeating unit called a sarcomere. Troponin is a component of thin filaments (along with tropomyosin), and is the protein to which calcium binds.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      22.2
      Seconds
  • Question 81 - The postextrasystolic potentiation of myocardial contractility is due to: ...

    Incorrect

    • The postextrasystolic potentiation of myocardial contractility is due to:

      Your Answer: Increased myocardial fiber length

      Correct Answer: Increase in intracellular Ca2+

      Explanation:

      The postextrasystolic potentiation of myocardial contractility Is not due to ventricular filling. It occurs in isolated locations in the heart and is due to increase availability of intracellular calcium.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      75.5
      Seconds
  • Question 82 - The initial rapid depolarization in the action potential of cardiac muscle cells is...

    Correct

    • The initial rapid depolarization in the action potential of cardiac muscle cells is due to:

      Your Answer: Opening of voltage-gated Na+ channels

      Explanation:

      The initial depolarization of the action potential in a cardiac muscle cell is due to the sodium current generated by opening of the voltage gated sodium channels leading to an influx of sodium ions into the cell and raising the membrane potential towards threshold.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      30.7
      Seconds
  • Question 83 - The ability of the SA node cells to allow ionic flow through channels...

    Correct

    • The ability of the SA node cells to allow ionic flow through channels activated in a hyperpolarized state is known as:

      Your Answer: Pace maker potential

      Explanation:

      Rhythmically discharging cells have a membrane potential that, after each impulse, declines to the firing level. Thus this prepotential or Pacemaker potential triggers the next impulse. The inherent leakiness of the sinus nodal fibers to Na+ and Ca2+ causes their self excitation.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      42.7
      Seconds
  • Question 84 - Nitric oxide triggers vascular smooth muscle contraction through activation of which enzyme? ...

    Correct

    • Nitric oxide triggers vascular smooth muscle contraction through activation of which enzyme?

      Your Answer: Guanylyl cyclase

      Explanation:

      Impaired production or excess catabolism of NO impairs this endothelium-dependent vasodilator function and may contribute to excessive vasoconstriction under various pathological situations.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.9
      Seconds
  • Question 85 - What are the diagnostic criteria for an ST segment elevation type of acute...

    Correct

    • What are the diagnostic criteria for an ST segment elevation type of acute myocardial infarction?

      Your Answer: 1 mm ST elevation in 2 limb leads

      Explanation:

      The current guidelines for the ECG diagnosis of the ST segment elevation type of acute myocardial infarction require at least 1 mm (0.1 mV) of ST segment elevation in the limb leads, and at least 2 mm elevation in the precordial leads. These elevations must be present in anatomically contiguous leads. (I, aVL, V5, V6 correspond to the lateral wall; V3-V4 correspond to the anterior wall ; V1-V2 correspond to the septal wall; II, III, aVF correspond to the inferior wall.)

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      46.4
      Seconds
  • Question 86 - Angina pectoris develops when blood through the coronary artery becomes: ...

    Incorrect

    • Angina pectoris develops when blood through the coronary artery becomes:

      Your Answer: Atherosclerotic

      Correct Answer: Restricted, limiting blood blow

      Explanation:

      Angina pectoris develops when stenosis ( >70%) of the artery occurs as a result of formation of an atherosclerotic plaque. This leads to a decrease in the O2 carried to the thickened heart muscle by the blood, leading to the characteristic chest pain associated with angina pectoris.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      21.4
      Seconds
  • Question 87 - In the jugular venous pressure wave… ...

    Correct

    • In the jugular venous pressure wave…

      Your Answer: Consists of 3 peaks and 2 troughs

      Explanation:

      The jugular venous pressure (JVP, sometimes referred to as jugular venous pulse) is the indirectly observed pressure over the venous system via visualization of the internal jugular vein. It can be useful in the differentiation of different forms of heart and lung disease. Classically three upward deflections (peaks) and two downward deflections (troughs) have been described:The upward deflections are the a (atrial contraction), c (ventricular contraction and resulting bulging of tricuspid into the right atrium during isovolumetric systole) and v = venous filling.The downward deflections of the wave are the x (the atrium relaxes and the tricuspid valve moves downward) and the y descent (filling of ventricle after tricuspid opening).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      166.2
      Seconds
  • Question 88 - Which of the following intercellular connections is important in endothelial barrier function? ...

    Correct

    • Which of the following intercellular connections is important in endothelial barrier function?

      Your Answer: Tight junctions

      Explanation:

      Tight junctions surround the apical margins of the epithelial cells such as in the intestinal mucosa and the choroid plexus. They are also important to the endothelial barrier function. They are made up of ridges that adhere to each other strongly at the cell junction, obliterating the space completely between the cells.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      17.5
      Seconds
  • Question 89 - The direct determinants of cardiac output are ...

    Correct

    • The direct determinants of cardiac output are

      Your Answer: Stroke volume and heart rate

      Explanation:

      Cardiac output is classically defined alongside stroke volume (SV) and the heart rate (HR) as:Cardiac Output [L/min] = Stroke Volume [L/beat] x Heart Rate [beats/min]

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      10.9
      Seconds
  • Question 90 - The positive inotropic effect of digoxin is due to? ...

    Incorrect

    • The positive inotropic effect of digoxin is due to?

      Your Answer: Stimulation of calcium channels

      Correct Answer: Inhibition of the sodium potassium ATPase in the myocardium

      Explanation:

      Digitalis compounds are potent inhibitors of cellular Na+/K+-ATPase. This ion transport system moves sodium ions out of the cell and brings potassium ions into the cell. By inhibiting the Na+/K+-ATPase, cardiac glycosides cause the intracellular sodium concentration to increase. This then leads to an accumulation of intracellular calcium via the Na+/Ca++ exchange system. In the heart, increased intracellular calcium causes more calcium to be released by the sarcoplasmic reticulum, thereby making more calcium available to bind to troponin-C, which increases contractility (inotropy).

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      12.7
      Seconds
  • Question 91 - Which of the following is first to rise following myocardial infarction? ...

    Incorrect

    • Which of the following is first to rise following myocardial infarction?

      Your Answer: Troponin I

      Correct Answer: Myoglobin

      Explanation:

      Myoglobin, is a sensitive indicator of muscle injury and is first to rise following MI within two hours but is nonspecific.Troponin and CK-MB both begin to rise approximately three hours after MI. The cardiac troponins T and I which are released within 4–6 hours of an attack of MI and remain elevated for up to 2 weeks, have nearly complete tissue specificity and are now the preferred markers for assessing myocardial damage.Lactate dehydrogenase (LDH) begins to rise approximately 12 hours after MI.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      16.5
      Seconds
  • Question 92 - In the cardiac cycle, all of the following are true except: ...

    Incorrect

    • In the cardiac cycle, all of the following are true except:

      Your Answer: The left ventricular pressure is maximal just before the aortic valve opens

      Correct Answer: Mitral valve is closed by contraction of papillary muscles

      Explanation:

      Mitral valve is closed by contraction of papillary muscles: This statement is incorrect. The mitral valve closes due to the pressure difference between the left ventricle and the left atrium at the onset of ventricular systole. The papillary muscles contract to prevent prolapse of the valve into the atrium but do not cause the valve to close.

      The left ventricular volume is maximal at the end of atrial systole: This statement is true. At the end of atrial systole, the atria have pushed the remaining blood into the ventricles, making the ventricular volume maximal (end-diastolic volume).

      The left ventricular pressure is maximal just before the aortic valve opens: This statement is true. Left ventricular pressure peaks just before the aortic valve opens, as the ventricle contracts to overcome the pressure in the aorta.

      The ejection fraction is about 55%: This statement is true. The ejection fraction, which is the percentage of blood ejected from the ventricles with each contraction, is typically around 55%.

      The ‘a’ wave is due to atrial systole: This statement is true. The ‘a’ wave on the venous pressure curve corresponds to atrial systole, reflecting the increased pressure from atrial contraction.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      56.9
      Seconds
  • Question 93 - The heart rate can be accelerated by: ...

    Incorrect

    • The heart rate can be accelerated by:

      Your Answer: Stimulation of pain fibers in the trigeminal nerve

      Correct Answer: Exercise and thyroid hormones

      Explanation:

      The firing of the SA node will increase due to exercises and as the thyroid hormone has a chronotropic effect on the heart, it too will result in an increase in the heart rate via stimulation of the adrenergic receptors of the heart. As during exercise the sympathetic nervous system is activated, it will directly have an positive chronotropic effect on the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      36.4
      Seconds
  • Question 94 - The coronary sinus drains into the: ...

    Correct

    • The coronary sinus drains into the:

      Your Answer: Right atrium

      Explanation:

      The coronary sinus drains into the right atrium. Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      11.6
      Seconds
  • Question 95 - Following an action potential, cytosolic Ca2+ is increased. The binding of free Ca2+...

    Incorrect

    • Following an action potential, cytosolic Ca2+ is increased. The binding of free Ca2+ to troponin C results in all of the following except:

      Your Answer: Exposure of actin binding site for myosin

      Correct Answer: Weakening of the troponin i interaction with actin

      Explanation:

      At rest, troponin i is bound to actin and tropomyosin and covers the site where the myosin head interacts with actin. When Calcium enters into the muscle, it binds with troponin C and cause a structural change in troponin i which moves out of the myosin binding site and causes the cross bridges between the actin and myosin filaments to occur.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      57.2
      Seconds
  • Question 96 - Which of the following is the most common causative organism in infective endocarditis?...

    Incorrect

    • Which of the following is the most common causative organism in infective endocarditis?

      Your Answer: Staphylococcus epidermidis

      Correct Answer: Streptococcus viridans

      Explanation:

      Viridans Alpha-haemolytic streptococci, that are present in the mouth are the most frequently isolated microorganisms when the infection is acquired in a community setting. In contrast, Staphylococcus blood stream infections are frequently acquired in a health care setting where they can enter the blood stream through procedures that cause break in the integrity of skin like surgery, catheterisation or during access of long term indwelling catheters or secondary to intravenous injection of recreational drugs.Prosthetic valve endocarditis is commonly caused by Staphylococcus epidermidis as it is capable of growing as a biofilm on plastic surfaces

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      18.1
      Seconds
  • Question 97 - The bradycardia that occurs in patients with raised intracranial pressure is a result...

    Incorrect

    • The bradycardia that occurs in patients with raised intracranial pressure is a result of the?

      Your Answer: Bezold jarisch reflex

      Correct Answer: Cushing reflex

      Explanation:

      When intracranial pressure is increased, the blood supply to RVLM neurons is compromised. This results in an increase in their discharge as a result of hypoxia and hypercapnia. The resultant rise in systemic arterial pressure (Cushing reflex) tends to restore the blood flow to the medulla.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      50.4
      Seconds
  • Question 98 - The following is true in relation to coronary venous drainage? ...

    Correct

    • The following is true in relation to coronary venous drainage?

      Your Answer: Most venous return ultimately drains into right atrium via the coronary sinus

      Explanation:

      Most of the venous blood returns to the heart via the coronary sinus and the anterior cardiac veins. Apart from these there are other vessels that drain directly into the heart chambers

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      35.9
      Seconds
  • Question 99 - Which of the following factors serve to decrease cardiac output? ...

    Correct

    • Which of the following factors serve to decrease cardiac output?

      Your Answer: Standing from a lying position

      Explanation:

      Sleep has no effect on the cardiac output. Anxiety, excitement, increased body temperature and pregnancy will increase the cardiac output. Standing from a lying position will decrease the cardiac output transiently.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      55.1
      Seconds
  • Question 100 - Which is the commonest cardiovascular abnormality seen in an adult patient with Marfan’s...

    Incorrect

    • Which is the commonest cardiovascular abnormality seen in an adult patient with Marfan’s syndrome?

      Your Answer: Aortic regurgitation

      Correct Answer: Aortic aneurysm

      Explanation:

      Marfan syndrome (MFS) is a genetic disorder of connective tissue. The degree to which people are affected varies. People with Marfan’s tend to be tall, and thin, with long arms, legs, fingers and toes. They also typically have flexible joints and scoliosis. The most serious complications involve the heart and aorta with an increased risk of mitral valve prolapse and aortic aneurysm.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14.6
      Seconds
  • Question 101 - Where would one normally find venous valves? ...

    Correct

    • Where would one normally find venous valves?

      Your Answer: Saphenous vein

      Explanation:

      The intima of the limb veins is folded at intervals to form venous valves that prevent retrograde flow. There are no valves present in the very small veins, the great veins, or the veins in the brain and viscera.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      15.9
      Seconds
  • Question 102 - The following is true of the sinus node: ...

    Correct

    • The following is true of the sinus node:

      Your Answer: It generates impulses automatically & at a quicker rate than other cardiac cells

      Explanation:

      The SA node exhibits automaticity. It generates the impulses to which the heart beats. It fires at a faster speed than the rest of the nervous components of the heart i.e. the AV nodes, purkinje fibers. This is the reason when the SA node fails the heart beats to the rhythm of the AV node.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      35.7
      Seconds
  • Question 103 - Which of the following are responsible for the 4th heart sound? ...

    Correct

    • Which of the following are responsible for the 4th heart sound?

      Your Answer: Ventricular hypertrophy

      Explanation:

      The fourth heart sound is not normally audible in a normal adult. It occurs as a consequence of ventricular hypertrophy. It is caused by filling of the ventricle in atrial systole.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      23
      Seconds
  • Question 104 - Concerning surface anatomy, where is the apex beat found? ...

    Correct

    • Concerning surface anatomy, where is the apex beat found?

      Your Answer: 5th intercostal space mid clavicular line

      Explanation:

      The location of the apex beat may vary but it is mostly found in the left 5th intercostal space 6 cm from the anterior median line or in the mid clavicular line.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      29.5
      Seconds
  • Question 105 - When observing a JVP, which of the following would lead to prominent v...

    Correct

    • When observing a JVP, which of the following would lead to prominent v waves?

      Your Answer: Tricuspid regurgitation

      Explanation:

      The v wave corresponds to Venous filling when the tricuspid valve is closed and venous pressure increases from venous return. In Tricuspid regurgitation there is additional blood from the regurgitant flow and thus this leads to a more prominent V wave.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      27.6
      Seconds
  • Question 106 - Which factor produced by the endothelium is responsible for the regulation of vascular...

    Correct

    • Which factor produced by the endothelium is responsible for the regulation of vascular cell growth?

      Your Answer: Vascular endothelial growth factor (VEGF)

      Explanation:

      VEGF is produced by the endothelial cells and is the major growth factor responsible for causing vasculogenesis. Some isoforms of this growth factor also have a prominent role in formation of lymphatic vessels.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      13.8
      Seconds
  • Question 107 - Which is the most common site for primary cardiac tumours to occur in...

    Incorrect

    • Which is the most common site for primary cardiac tumours to occur in adults?

      Your Answer: Right atrium

      Correct Answer: Left atrium

      Explanation:

      Myxomas are the most common type of primary heart tumour. The tumour is derived from multipotential mesenchymal cells and may cause a ball valve-type obstruction. About 75% of myxomas occur in the left atrium of the heart, usually beginning in the wall that divides the two upper chambers of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      12.4
      Seconds
  • Question 108 - The internodal tract of Bachman: ...

    Correct

    • The internodal tract of Bachman:

      Your Answer: Connects the SA node to the AV node

      Explanation:

      Internodal tract of Bachman connects the SA node to the AV node conducting the electrical impulses generated from the SA node to the AV node and from the AV node to the rest of the electrical complex of the heart.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      67.4
      Seconds
  • Question 109 - Hyperkalaemia [K+ =7meq/l] can lead to the following ECG changes [Ca++ normal] ...

    Correct

    • Hyperkalaemia [K+ =7meq/l] can lead to the following ECG changes [Ca++ normal]

      Your Answer: Peaked T waves

      Explanation:

      Hyperkalaemia causes the formation of tall tented T waves due to altered repolarization.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      14
      Seconds
  • Question 110 - Which part of the ECG represents ventricular repolarisation? ...

    Correct

    • Which part of the ECG represents ventricular repolarisation?

      Your Answer: T wave

      Explanation:

      Ventricular repolarisation is denoted by the T wave.

    • This question is part of the following fields:

      • Cardiovascular
      • Medicine
      22.2
      Seconds

SESSION STATS - PERFORMANCE PER SPECIALTY

Cardiovascular (64/110) 58%
Medicine (64/110) 58%
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